﻿Shader "Custom/Particle" {
	Properties {
		_Color ("Color", Color) = (1,1,1,1)
		_Glossiness ("Smoothness", Range(0,1)) = 0.5
		_Metallic ("Metallic", Range(0,1)) = 0.0
	}
	SubShader {
		Tags { "RenderType"="Opaque" }
		LOD 200

		Cull Off

		CGPROGRAM
		// Physically based Standard lighting model, and enable shadows on all light types
		#pragma surface surf Standard fullforwardshadows addshadow

		// Use shader model 3.0 target, to get nicer looking lighting
		#pragma target 3.0


		struct Input {
			INTERNAL_DATA
			float3 worldNormal;
			float3 worldPos;
		};

		half _Glossiness;
		half _Metallic;

		// Add instancing support for this shader. You need to check 'Enable Instancing' on materials that use the shader.
		// See https://docs.unity3d.com/Manual/GPUInstancing.html for more information about instancing.
		// #pragma instancing_options assumeuniformscaling
		UNITY_INSTANCING_BUFFER_START(Props)
			UNITY_DEFINE_INSTANCED_PROP(fixed4, _Color)
		UNITY_INSTANCING_BUFFER_END(Props)

		void surf (Input IN, inout SurfaceOutputStandard o) {
			// Albedo comes from a texture tinted by color
			fixed4 c = UNITY_ACCESS_INSTANCED_PROP(Props, _Color);
			o.Albedo = c.rgb;
			// Metallic and smoothness come from slider variables
			o.Metallic = _Metallic;
			o.Smoothness = _Glossiness;
			o.Alpha = c.a;

			if (dot(IN.worldNormal,(IN.worldPos-_WorldSpaceCameraPos))<0.f) {
				o.Normal=float3(0,0,-1);
			} else {
				o.Normal=float3(0,0,1);
			}
		}
		ENDCG
	}
	FallBack "Diffuse"
}
